The present invention relates in general to a printing blanket sleeve and in particular to a seamless printing blanket sleeve having a replaceable printing surface.
A typical blanket cylinder on an offset printing press includes an axially extending groove, or lock up gutter with clamping segments. Printing blankets are provided in sheets that are wrapped around the blanket cylinder such that the opposite ends of the printing blanket are inserted and clamped in the groove. Because the loose ends of the blanket must be secured to the cylinder, the surface of the blanket when mounted will have a gap where the edges are drawn. As a consequence, print quality, speed of operation, and available print region dimensions are affected. Press downtime, including printing blanket change over time, can also be excessive.
These problems can be minimized where the printing blanket is provided as a gapless sleeve that is capable of mounting onto the blanket cylinder. Because the sleeve is essentially stretched while on the blanket cylinder however, the sleeve is exposed to considerable peripheral and circumferential forces. Additionally, while operating the press, the blanket sleeve is exposed to high revolution speeds and impact with other components of the press, including a plate cylinder with printing plates. As such, the printing blanket sleeve will eventually dynamically fatigue. Where the printing blanket sleeve has experienced sufficient dynamic fatigue, print quality will be affected, and the printing blanket sleeve must be replaced. However, it is usually either the printing surface, or the adhesive that holds the printing surface to the first internal layer, that will fail. The remaining layers are often functionally intact.
Currently, some fatigued printing blanket sleeves are discarded. This leads to considerable waste and cost as the materials used to construct the base layer and internal layers constitute a significant portion of the total materials cost for the sleeve production. Alternatively, the fatigued printing blanket sleeves are sent back to the manufacturer to be reconditioned or “recapped”. While reconditioning allows for recycling of certain reusable portions of the fatigued printing blanket sleeve, the press operator must ship the entire printing blanket sleeve back to the manufacturer. The manufacturer must remove the worn portions of the printing blanket sleeve, and assemble a new printing surface and internal components to the printing blanket sleeve. This causes considerable cost to the manufacturer. Further, some sleeves returned to the manufacturer have damage to the nickel base from shipping or handling and cannot be reprocessed.
Therefore, there is a need for a gapless printing blanket that allows for a simple changeover of the printing surface of a fatigued printing blanket sleeve, where the changeover can be accomplished directly on the press, or on-site, near the press.